Evaluation of calibration factors of digital survey meters in a secondary standard dosimetry laboratory.

The calibration of radiological survey meters is an important consideration in achieving standardisation of doses. This provides traceability for field instruments to an International System of Units. Seventy-one digital survey meters were calibrated by the substitution method in a 137Cs beam in a secondary standard dosimetry laboratory using a PTW spherical ionisation chamber coupled to a Physikalisch-Technische-Werkstaetten (PTW) UNIDOS Electrometer. The calibration factors determined ranged from 0.59 to 1.98. Thirty-six pieces of equipment have their calibration factors within 0.9-1.1. A total of 36% of the survey meters recorded calibration factors corresponding to a percentage deviation above 20% whilst 64% fell within 20% deviations from the true value. The best value of a calibration factor obtained in this work was 1.00 from two survey meters. The errors due to survey meters being out of calibration can usually be corrected by frequent recalibration.

The Evolving Effectiveness of Biologics in Avoiding Surgery in Children With Ulcerative Colitis: At what Nutritional Cost?

BACKGROUND: Pediatric ulcerative colitis (UC) treatment has changed dramatically with the introduction of multiple biologics. The goal of this study was to determine the effectiveness of these new biologics on achieving remission, nutritional impact, and eventual need for surgery in children. METHODS: We retrospectively analyzed hospital records of UC patients (ages 1-19) seen at a pediatric gastroenterology clinic between January 2012 andAugust 2020. Patients were divided into groups: 1) medically without biologics or surgery; 2) patients treated with one biologic; and 3) patients treated with multiple biologics 4)patients that underwent colectomy. RESULTS: There were 115 UC patients with a mean follow-up of 5.9 ± 3.7 years (1 month-15.3 years). PUCAI score at diagnosis was mild in 52 patients (45%), moderate in 25 (21%), and severe in 5 (4.3%). PUCAI score for 33 patients (29%) could not be calculated. There were 48 (41.3%) in group 1 with 58% remission, 34 (29.6%) in group 2 with 71% remission, 24 (20.8%) in group 3 with 29% remission, and only 9 (7.8%) in group 4 with 100% remission. The majority (55%) of surgical patients had colectomy within the first year of diagnosis. BMI improved after surgery (P = 0.001). The change from one biologic to others did not improve nutrition over time. DISCUSSION: New biologics are changing the landscape in maintaining remission from UC. The current need for surgery is much lower than previously published studies. In medically refractive UC, nutritional status only improved after surgery. Addition of another biologic for medically refractory ulcerative colitis in order to avoid surgery must take into account the positive impact surgery has on nutrition and disease remission.

Incidence of venous thromboembolism in patients with sickle cell disease undergoing noncardiovascular surgery.

OBJECTIVE: Patients with sickle cell disease (SCD) will have a baseline hypercoagulable state and an increased risk of venous thromboembolism (VTE). Few data are available regarding the efficacy of standard prophylaxis in preventing VTE after noncardiovascular surgery for patients with SCD. Our objective was to investigate the incidence of VTE in patients with SCD who had undergone noncardiovascular surgery. METHODS: We performed a retrospective medical record review of 352 patients with SCD who had undergone noncardiovascular surgery from August 2009 to August 2019 at Beaumont Hospitals. An equal number of control patients without SCD were propensity matched for age, sex, race, body mass index, and specific surgery. The data collected included demographics, comorbidities, VTE prophylaxis used, occurrence of deep vein thrombosis (DVT) and pulmonary embolism (PE), hospital length of stay, and 30-day mortality. RESULTS: We found no differences in age, race, sex, ethnicity, operative time, or hospital length of stay between the SCD and propensity-matched control patients. DVT prophylaxis was used more frequently for the SCD patients than for the controls (96.0% vs 88.6%; P < .001). Four SCD patients (1.1%) had developed DVT vs five control patients (1.4%; P > .999). One patient in each group had developed PE (0.3%; P > .999). No difference was found in 30-day mortality between the SCD group and the control group (1 [0.3%] vs 3 [0.9%]; P = .312). Of those with a diagnosis of VTE ≤30 days postoperatively, no differences were present in age, sex, race, BMI, or procedure type. DVT had been diagnosed significantly later in the SCD patients than in the controls (median, postoperative day 12 vs 5; P = .014). None of the five SCD patients with VTE was a smoker compared with four of the six non-SCD patients with VTE, who were current or former tobacco users (P = .061). All the patients who had developed VTE had received DVT prophylaxis at surgery. CONCLUSIONS: We found no differences in the perioperative rates of DVT, PE, or mortality between the SCD patients and matched control patients after noncardiovascular surgery. Vigilant attention to routine VTE prophylaxis seemed to effectively reduce the VTE risk for these hypercoagulable patients. SCD patients might need VTE prophylaxis for a longer period postoperatively compared with those without SCD.

ASSESSMENT OF RADIOFREQUENCY RADIATION WITHIN THE VICINITY OF SOME GSM BASE STATIONS IN GHANA: A FOLLOW-UP.

A follow-up of radiofrequency (RF) electromagnetic radiation safety survey at public access points had been carried out in 46 towns on 76 Global Systems for Mobile Communications and Universal Mobile Telecommunication System cell sites in two major cities in Ghana. The core objective was to determine the RF field levels in residential areas, schools and marketplaces and compare the measured results with the guidelines set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Measurements were made with calibrated log-periodic antenna coupled with a spectrum analyzer. The results obtained varied from 0.0008 to 182 mW m -2, which generally shows compliance with the ICNIRP reference levels. The highest value was 1.39 % of the reference.